Thanks. If WAN IP is private then to my best understanding DDNS won't work. I mean DDNS will push that private IP in DNS which goes nowhere as it's not routable. So I am not too sure what's the benefit of that setting.

@ramki_87 

 

If a router's WAN IP address is private, then the DDNS service running on it will usually attempt to find the external public IP address by contacting a server on the internet, a commonly used one being "http://checkip.dyndns.org".

 

Now, there could be two reasons why the WAN IP address of the router is a private one.

 

1) The Internet Service Provider is assigning private IP addresses to the customer's Internet connection, to limit the amount of public IPv4 addresses they need to buy from the authorities.
In this case it would be useless for the customer to activate the DDNS service on the home router.

 

2) The router (or other network device like IP camera, NAS server, computer, etc.) that is running the DDNS service is not directly connected to the Internet connection, but instead is connected as a client device to, for example, an ISP-supplied modem router that obtains a public IP address.
If that ISP-supplied modem router doesn't feature its own DDNS service, then you could still use the DDNS service of a network device that is connected to the ISP-supplied router.
To make the whole thing useful you would of course also need to configure port forwarding on the ISP-supplied modem router.